Authentication system, mobile device, processing device, and non-transitory computer-readable medium

ABSTRACT

A mobile device is carried by a person to be authenticated. An acceleration sensor is installed in the mobile device and configured to output an acceleration signal corresponding to acceleration applied to the mobile device. A processing device is configured to execute determination processing for determining whether the person is walking based on the acceleration signal. A control device is configured to control transmission of a radio signal, and to control an operation of a controlled device based on a result of the determination processing and a result of authentication processing for authenticating, by way of the mobile device, the person as a user of the controlled device. The determination processing is activated in response to reception of the radio signal by the mobile device.

FIELD

The presently disclosed subject matter relates to an authenticationsystem. The presently disclosed subject matter also relates to a mobiledevice and a processing device that may be included in theauthentication system. The presently disclosed subject matter alsorelates to a non-transitory computer-readable medium having recorded acomputer program adapted to be executed by a processor of the processingdevice.

BACKGROUND

Japanese Patent Publication No. 2016-211334A discloses an authenticationsystem adapted to be installed in a vehicle. In the system,authentication is performed between a control device for controlling theoperation of a locking device, which is an example of a controlleddevice, and a key, which is an example of a mobile device owned by aperson to be authenticated, through communication with a radio wave.When the authentication is approved, the door of the vehicle isunlocked.

SUMMARY Technical Problem

It is demanded to improve the convenience of such an authenticationsystem.

Solution to Problem

In order to meet the demand described above, a first illustrative aspectof the presently disclosed subject matter provides an authenticationsystem, comprising:

a mobile device adapted to be carried by a person to be authenticated;

an acceleration sensor installed in the mobile device and configured tooutput an acceleration signal corresponding to acceleration applied tothe mobile device;

a processing device configured to execute determination processing fordetermining whether the person is walking based on the accelerationsignal; and

a control device configured to control transmission of a radio signal,and to control an operation of a controlled device based on a result ofthe determination processing and a result of authentication processingfor authenticating, by way of the mobile device, the person as a user ofthe controlled device,

wherein the determination processing is activated in response toreception of the radio signal by the mobile device.

In order to meet the demand described above, a second illustrativeaspect of the presently disclosed subject matter provides a mobiledevice adapted to be carried by a person to be authenticated,comprising:

a receiver configured to receive a radio signal

an acceleration sensor configured to output an acceleration signalcorresponding to acceleration applied to the mobile device; and

a processor configured to execute determination processing fordetermining whether the person is walking based on the accelerationsignal, and to output a result of the determination processing to acontrol device configured to execute authentication processing forauthenticating the person as a user of a controlled device,

wherein the determination processing is activated in response toreception of the radio signal by the receiver.

According to the configuration according to each of the first and secondillustrative aspects, the result of the determination processing fordetermining whether a person to be authenticated is walking can be usedfor the authentication processing for authenticating the person as auser of the controlled device. In addition, since the determinationprocessing is activated in response to reception of the radio signal bythe mobile device, the acceleration sensor and the determinationprocessing are in a standby state until the mobile device receives theradio signal. Since power consumption in the mobile device can besuppressed, it is accordingly possible to improve the convenience of theauthentication system.

In order to meet the demand described above, a third illustrative aspectof the presently disclosed subject matter provides an authenticationsystem, comprising:

a mobile device adapted to be carried by a person to be authenticated;

an acceleration sensor installed in the mobile device and configured tooutput an acceleration signal corresponding to acceleration applied tothe mobile device;

a processing device configured to define a time period as time between afirst time point and a second time point at which the accelerationsignal satisfies a prescribed condition, and to execute determinationprocessing for determining whether the person is walking based on afeature quantity associated with a waveform portion of the accelerationsignal within the time period; and

a control device configured to control an operation of a controlleddevice based on a result of the determination processing and a result ofauthentication processing for authenticating, by way of the mobiledevice, the person as a user of the controlled device.

In order to meet the demand described above, a fourth illustrativeaspect of the presently disclosed subject matter provides a mobiledevice adapted to be carried by a person to be authenticated,comprising:

an acceleration sensor configured to output an acceleration signalcorresponding to acceleration applied to the mobile device; and

a processor configured to: define a time period as time between a firsttime point and a second time point at which the acceleration signalsatisfies a prescribed condition; to execute determination processingfor determining whether the person is walking based on a featurequantity associated with a waveform portion of the acceleration signalwithin the time period; and to output a result of the determinationprocessing to a control device configured to execute authenticationprocessing for authenticating the person as a user of a controlleddevice.

In order to meet the demand described above, a fifth illustrative aspectof the presently disclosed subject matter provides a processing device,comprising:

a reception interface configured to accept an acceleration signalcorresponding to acceleration applied to a mobile device adapted to becarried by a person to be authenticated from an acceleration sensorinstalled in the mobile device; and

a processor configured to: define a time period as time between a firsttime point and a second time point at which the acceleration signalsatisfies a prescribed condition; to execute determination processingfor determining whether the person is walking based on a featurequantity associated with a waveform portion of the acceleration signalwithin the time period; and to output a result of the determinationprocessing to a control device configured to execute authenticationprocessing for authenticating, by way of the mobile device, the personas a user of a controlled device.

In order to meet the demand described above, a sixth illustrative aspectof the presently disclosed subject matter provides a non-transitorycomputer-readable medium having stored a computer program adapted to beexecuted by a processor of a processing device and configured to, whenexecuted, cause the processing device to:

accept an acceleration signal corresponding to acceleration applied to amobile device adapted to be carried by a person to be authenticated froman acceleration sensor installed in the mobile device;

define a time period as time between a first time point and a secondtime point at which the acceleration signal satisfies a prescribedcondition;

execute determination processing for determining whether the person iswalking based on a feature quantity associated with a waveform portionof the acceleration signal within the time period; and

output a result of the determination processing to a control deviceconfigured to execute authentication processing for authenticating, byway of the mobile device, the person as a user of a controlled device.

According to the configuration according to each of the third to sixthillustrative aspects, the result of the determination processing fordetermining whether a person to be authenticated is walking can be usedfor the authentication processing for authenticating the person as auser of the controlled device. In addition, the time period is definedbased on a condition prescribed so as to include a waveform portion inthe acceleration signal outputted from the acceleration sensor that mayrepresent a state that the person to be authenticated is walking.Furthermore, by referring to the feature quantity for the waveformportion, it is verified whether the person to be authenticated iswalking. Since the accuracy of the walking determination processing isimproved, it is accordingly possible to improve the convenience of theauthentication system.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a configuration of an authentication system accordingto an embodiment.

FIG. 2 illustrates a detailed functional configuration of theauthentication system.

FIG. 3 illustrates a flow of processing executed in a control device ofthe authentication system.

FIG. 4 illustrates a flow of processing executed in a mobile device ofthe authentication system.

FIG. 5 illustrates a flow of processing in a walking determinationprocessing of FIG. 4 .

FIG. 6 illustrates details of the walking determination processing.

FIG. 7 illustrates details of the walking determination processing.

FIG. 8 illustrates details of the walking determination processing.

FIG. 9 illustrates a flow of processing in an activation processing ofFIG. 4 .

DESCRIPTION OF EMBODIMENTS

Examples of embodiments will be described in detail below with referenceto the accompanying drawings. FIG. 1 illustrates a configuration of anauthentication system 10 according to an embodiment. The authenticationsystem 10 may be used, for example, to authenticate a person 20 to beauthenticated (hereinafter, referred to as an authenticated person 20,or a person 20) as a user of a vehicle 30 thereby allowing theauthenticated person 20 to use the vehicle 30.

The authentication system 10 includes a mobile device 11. The mobiledevice 11 is a device capable of being carried by the authenticatedperson 20.

The authentication system 10 includes a control device 12. In thisexample, the control device 12 is installed in the vehicle 30. Thecontrol device 12 is configured to control the operation of a controlleddevice 31 installed in the vehicle 30 based on an authenticationprocessing for authenticating the person 20 as a user of the vehicle 30via the mobile device 11. In FIG. 1 , a locking device 311 and an engine312 are illustrated as controlled devices 31. The controlled devices 31may also include an air conditioner, an audio-visual equipment, alighting device, a position adjustment mechanism for a seat or asteering wheel, and the like.

As used herein, the term “authentication process” means a processincluding a process of authenticating the person 20 itself as a user,and a process of authenticating the mobile device 11 itself owned by theauthenticated person 20 as a user.

The authentication system 10 includes a processing device 13. Theprocessing device 13 is configured to execute an authentication processin cooperation with the control device 12. In this example, theprocessing device 13 is installed in the mobile device 11.

The authentication processing will be described in detail with referenceto FIG. 2 . The control device 12 includes a processor 121. Theprocessor 121 is configured to control wireless transmission of atrigger signal TS from a transmitter 32 installed in the vehicle 30. Thetrigger signal TS is transmitted at prescribed time intervals. Theprescribed time interval is, for example, several hundred milliseconds.The trigger signal TS may be an analog signal or a digital signal. Itshould be noted that the trigger signal TS may be constantly transmittedfrom the transmitter 32 regardless of the operation of the controldevice 12. The tringger signal TS is an example of the radio signal.

The processing device 13 includes a reception interface 131 and aprocessor 132. The reception interface 131 is configured as an interfacecapable of accepting the trigger signal TS through a receiver 111installed in the mobile device 11. When the trigger signal TS is ananalog signal, the reception interface 131 may be equipped with anappropriate conversion circuit including an A/D converter. The triggersignal TS in the form of digital data is subjected to processingperformed by the processor 132.

The processor 132 is configured to wirelessly transmit an authenticationinformation AI through the transmitter 112 installed in the mobiledevice 11 in response to the trigger signal TS. The authenticationinformation AI is information capable of identifying at least one of theauthenticated person 20 and the mobile device 11.

That is, when the authenticated person 20 carrying the mobile device 11approaches the vehicle 30 to a distance capable of receiving the triggersignal TS, the authentication information AI is transmitted from themobile device 11. The authentication information AI may be in the formof analog data or digital data.

The control device 12 includes a reception interface 122. The receptioninterface 122 is configured as an interface capable of accepting theauthentication information AI through a receiver 33 installed in thevehicle 30. In a case where the authentication information AI is in theform of analog data, the reception interface 122 may be equipped with anappropriate conversion circuit including an A/D converter. Theauthentication information AI in the form of digital data is subjectedto processing performed by the processor 121.

The processor 121 of the control device 12 is configured to be capableof executing a processing for reading or referencing the authenticationinformation AI stored in a storage device 34 installed in the vehicle30. The processor 121 matches the authentication information AI acceptedby the reception interface 122 with the authentication information AIstored in the storage device 34, and approves authentication when bothmatch.

The control device 12 includes an output interface 123. The processor121 allows the output of a control signal CS from the output interface123. The control signal CS is a signal for controlling the operation ofthe controlled device 31. The control signal CS may be a digital signalor an analog signal. In a case where the control signal CS is an analogsignal, the output interface 123 may be equipped with an appropriateconversion circuit including a D/A converter.

For example, the control signal CS may be a signal for causing thelocking device 311 to unlock the door of the vehicle 30. Alternatively,the control signal CS may be a signal for activating the engine 312.That is, when the person 20 is authenticated as a user of the vehicle 30through the wireless communication performed between the mobile device11 and the control device 12, the door of the vehicle 30 is unlocked andthe engine 312 is activated.

FIG. 3 illustrates a flow of processing executed by the control device12. As described above, the control device 12 wirelessly transmits thetrigger signal TS at prescribed time intervals through the transmitter32 installed in the vehicle 30 (STEP11).

FIG. 4 illustrates a flow of processing executed by the mobile device11. When the authenticated person 20 carrying the mobile device 11approaches the vehicle 30, the trigger signal TS wirelessly transmittedfrom the control device 12 installed in the vehicle 30 is wirelesslyreceived by the mobile device 11. As a result, an activation processingis executed (STEP21). In the activation processing, the above-describedauthentication information AI is wirelessly transmitted.

As illustrated in FIG. 3 , in the control device 12, it is determinedwhether the authentication for the person 20 is approved based on theauthentication information AI wirelessly transmitted from the mobiledevice 11 (STEP12). When the wireless reception of the authenticationinformation AI through the receiver 33 installed in the vehicle 30 isnot performed, or when the wirelessly received authenticationinformation AI does not match the authentication information stored inthe storage device 34 (NO in STEP12), the processing returns to STEP11.

As illustrated in FIG. 4 , in the mobile device 11, a walkingdetermination processing for determining whether the authenticatedperson 20 is walking is executed (STEP22). Details of the walkingdetermination processing will be described later.

When it is determined that the authenticated person 20 is not walking asa result of the walking determination processing (NO in STEP23), theprocessor 132 of the processing device 13 wirelessly transmits theenablement information EI through the transmitter 112 of the mobiledevice 11 (STEP24). The enablement information EI may be in the form ofanalog data or may be in the form of digital data.

When it is determined that the authenticated person 20 is walking as aresult of the walking determination processing (YES in STEP23), theprocessor 132 of the processing device 13 wirelessly transmits thedisablement information DI through the transmitter 112 of the mobiledevice 11 (STEP25). The disablement information DI may be in the form ofanalog data or may be in the form of digital data.

After the transmission of the enablement information EI or thedisablement information DI, the processing returns to STEP22, and thewalking determination processing is repeated. As illustrated by dashedlines in FIG. 4 , the processor 132 may disable the transmission of theenablement information EI instead of the transmission of the disablementinformation DI.

As illustrated in FIG. 2 , the enablement information EI and thedisablement information DI wirelessly transmitted from the transmitter112 of the mobile device 11 are wirelessly received by the receiver 33of the vehicle 30. The reception interface 122 of the control device 12is configured as an interface capable of accepting the enablementinformation EI and the disablement information DI. In a case where eachof the enablement information EI and the disablement information DI isin the form of analog data, it may be equipped with an appropriateconversion circuit including an A/D converter. The enablementinformation EI and the disablement information DI in the form of digitaldata are subjected to processing performed by the processor 121.

As illustrated in FIG. 3 , when the authentication for the person 20 isapproved (YES in STEP12), the processor 121 of the control device 12determines whether the enablement information EI is accepted from themobile device 11 (STEP13). When the enablement information EI isaccepted (YES in STEP13), the processor 121 enables the control of thecontrolled device 31 (STEP14). That is, a control signal CS for causingthe controlled device 31 to perform a prescribed operation in accordancewith the approval of the authentication is outputted from the outputinterface 123.

When the reception interface 122 receives the disablement information DIor when the enablement information EI is not transmitted from the mobiledevice 11 (NO in STEP13), the processor 121 disables the control of thecontrolled device 31 (STEP15). That is, the output of the control signalCS is not performed.

According to the configuration as described above, the result of thewalking determination processing can be used for the authenticationprocessing performed by the control device 12. For example, even if theauthentication of the person 20 is approved, when it is determined thatthe authenticated person 20 is walking, the control of the operation ofthe controlled device 31 by the control device 12 can be disabled. Theauthenticated person 20 normally does not walk when unlocking the doorof the vehicle 30 or activating the engine 312 by way of theauthentication processing. According to the configuration of the presentembodiment, the control of the operation of the controlled device 31 isenabled by the control device 12 when it is determined that theauthentication is approved and the authenticated person 20 is notwalking.

The processor 121 having the above-described function can be implementedby a general-purpose microprocessor operating in cooperation with ageneral-purpose memory. Examples of the general-purpose microprocessorinclude a CPU, an MPU, and a GPU. Examples of the general-purpose memoryinclude a ROM and a RAM. In this case, a computer program for executingthe above-described processing can be stored in the ROM. The ROM is anexample of a non-transitory computer-readable medium having recorded acomputer program. The general-purpose microprocessor designates at leasta part of a computer program stored in the ROM, loads the program on theRAM, and executes the processing described above in cooperation with theRAM. The above-described computer program may be pre-installed in thegeneral-purpose memory, or may be downloaded from an external serverdevice 50 via a wireless communication network 40 illustrated in FIG. 1and then installed in the general-purpose memory. In this case, theexternal server device 50 is an example of a non-transitorycomputer-readable medium having stored a computer program.

The processor 121 having the above-described function may be realized bya dedicated integrated circuit capable of executing the above-describedcomputer program, such as a microcontroller, an ASIC, and an FPGA. Inthis case, the above-described computer program is pre-installed in amemory element included in the dedicated integrated circuit. The memoryelement is an example of a non-transitory computer-readable mediumhaving stored a computer program. The processor 121 may be implementedby a combination of the general-purpose microprocessor and the dedicatedintegrated circuit.

Next, the details of the walking determination processing executed bythe processing device 13 in order to realize the operation of theauthentication system 10 as described above will be described.

As illustrated in FIG. 2 , the mobile device 11 includes an accelerationsensor 113. The acceleration sensor 113 is configured to output anacceleration signal AS corresponding to an acceleration applied to themobile device 11. The acceleration sensor 113 may be, for example, awell-known three-axis acceleration sensor. In this case, theacceleration signal AS has a value corresponding to the acceleration ineach of the three mutually orthogonal axes. The acceleration signal ASmay be an analog signal or a digital signal.

The reception interface 131 of the processing device 13 is configured asan interface capable of receiving the acceleration signal AS. In a casewhere the acceleration signal AS is an analog signal, the receptioninterface 131 may be equipped with an appropriate conversion circuitincluding an A/D converter. The acceleration signal AS in the form ofdigital data is subjected to processing performed by the processor 132of the processing device 13.

The processor 132 is configured to execute the walking determinationprocessing for determining whether the authenticated person 20 iswalking based on the acceleration signal AS. FIG. 5 illustrates a flowof the walking determination processing. FIG. 6 illustrates theacceleration signal AS. In FIG. 6 , the horizontal axis represents theelapse of time, and the vertical axis represents the acceleration. Sincethe attitude of the mobile device 11 is not constant, the value of theacceleration illustrated corresponds to a norm value given as the squareroot of the values of the acceleration in the respective three axes. Inthe following descriptions, “acceleration” means a “norm value” unlessotherwise specified.

When the acquisition of the acceleration signal AS is initiated at atime point t0, the processor 132 determines whether a time period TP(described later) is defined (STEP30). Here, since it is immediatelyafter the initiation of the walking determination processing (NO inSTEP30), the processor 132 determines whether the accelerationcorresponding to the acceleration signal AS satisfies a prescribedcondition (STEP31).

In this example, it is determined whether the acceleration changes froma value more than a threshold At to a value less than the threshold At,as well as whether an amount of change in the acceleration per unit time(i.e., a downslope gradient) exceeds a threshold. A relatively largeacceleration is applied to the mobile device 11 carried by the walkingauthenticated person 20, and the amount of change tends to be relativelylarge. This condition corresponds to this phenomenon.

In FIG. 6 , in order to facilitate understanding, the threshold At ofthe acceleration assumes a constant value. However, the threshold At maybe redefined as an average value of the acceleration every time when aprescribed time period elapses. The time is, for example, 500milliseconds.

When the above condition as for the change in the acceleration is notsatisfied (NO in STEP31), the processor 132 determines whether aprescribed time period has elapsed (STEP32). The time period is, forexample, 1 second. When it is determined that the prescribed time periodhas not elapsed (NO in STEP32), the processing returns to STEP31.

When the above-described condition as for the change in the accelerationis not satisfied and the prescribed time period elapses (YES in STEP32),the processor 132 determines that the authenticated person 20 is notwalking (STEP33), and terminates the processing. The result of thisdetermination is reflected in the determination in STEP23 of FIG. 4 .That is, the mobile device 11 wirelessly transmits the enablementinformation EI (STEP24). The control device 12 installed in the vehicle30 accepts the enablement information EI via the receiver 33.Accordingly, the operation of the controlled device 31 can be enabled bythe control device 12 (YES in STEP13 and STEP14 of FIG. 3 ).

When the above-described condition as for the change in the accelerationis satisfied (YES in STEP31), the processor 132 defines a start point ofthe time period for performing the walking determination processing(STEP34). In the example illustrated in FIG. 6 , the above condition asfor the acceleration change is satisfied at a time point t1 after thetime point t0. Accordingly, the processor 132 defines a start point SPof the time period TP at the time point t1. The start point SP is anexample of the first time point.

Subsequently, the processor 132 determines whether the accelerationcorresponding to the acceleration signal AS satisfies the condition asfor the above-described acceleration change again (STEP35 in FIG. 5 ).When the condition is not satisfied (NO in STEP35), the processor 132determines whether a prescribed time period has elapsed (STEP36). Thetime period is, for example, 1 second. When it is determined that theprescribed time period has not elapsed (NO in STEP36), the processingreturns to STEP35.

When the above-described condition as for the change in the accelerationis not satisfied again and the prescribed time period elapses (YES inSTEP36), the processor 132 determines that the authenticated person 20is not walking (STEP33), and terminates the processing. The result ofthis determination is reflected in the determination in STEP23 of FIG. 4. In this case, the mobile device 11 wirelessly transmits the enablementinformation EI (STEP24). The control device 12 installed in the vehicle30 accepts the enablement information EI via the receiver 33.Accordingly, the operation of the controlled device 31 can be enabled bythe control device 12 (YES in STEP13 and STEP14 of FIG. 3 ).

When the above condition as for the change in the acceleration issatisfied again (YES in STEP35 in FIG. 5 ), the processor 132 defines anend point of the time period for performing the walking determinationprocessing (STEP37). In the example illustrated in FIG. 6 , the abovecondition as for the acceleration change is satisfied again at a timepoint t2 after the time point t1. Accordingly, the processor 132 definesan end point EP of the time period TP at the time point t2. The endpoint EP is an example of the second time point.

Based on the temporal change (waveform) of the acceleration included inthe time period TP thus defined, it is determined whether theauthenticated person 20 is walking (STEP38). Specifically, thedetermination is made based on a plurality of feature quantitiesillustrated in FIG. 7 . The value of each feature quantity and thedetermination result as to whether the authenticated person 20 iswalking are associated with each other based on machine learning,statistical processing, or the like performed in advance. For example,the processor 132 determines whether the authenticated person 20 iswalking based on whether each value of the feature quantities to bereferred to falls within a prescribed threshold range. Examples of thefeature quantities are as follows. It should be noted that all thefeature quantities need not to be referred to, but at least one of thefeature quantities may be referred to.

-   T0: a length of the time period TP (a time length from the start    point SP to the end point EP)-   T1: a time length from the starting point SP to a time point when    the acceleration takes a maximum value Amx-   T2: a time length from a time point when the acceleration takes a    minimum value Amn to the time point when the acceleration takes the    maximum value Amx-   A: a difference between the maximum value Amx and the minimum value    Amn-   G0: an amount of change in acceleration per unit time from the time    point when the acceleration takes the minimum value Amn to the time    point when the acceleration takes the maximum value Amx-   M0: a mean value of the acceleration in the time period TP-   M1: a mean value of the acceleration in a period from the start    point SP to a time point HP that corresponds half the time period TP-   M2: a mean value of the acceleration in a period from the time point    HP to the end point EP

When it is determined that a waveform portion of the acceleration signalAS included in the time period TP between the time point t1 and the timepoint t2 does not satisfy the condition as for walking (NO in STEP38),the processor 132 determines that the authenticated person 20 is notwalking (STEP33), and then terminates the processing. The result isreflected in the processing of STEP23 in FIG. 4 . That is, after thetime point t2, the mobile device 11 wirelessly transmits the enablementinformation EI (STEP24). The control device 12 installed in the vehicle30 accepts the enablement information EI via the receiver 33.Accordingly, the operation of the controlled device 31 can be enabled bythe control device 12 (YES in STEP13 and STEP14 of FIG. 3 ).

When it is determined that the waveform portion of the accelerationsignal AS included in the time period TP between the time point t1 andthe time point t2 satisfies the condition as for walking (YES inSTEP38), the processor 132 determines that the authenticated person 20is walking (STEP39), and terminates the processing. The result isreflected in the processing of STEP23 in FIG. 4 . That is, after thetime point t2, the mobile device 11 wirelessly transmits the disablementinformation DI (STEP25). The control device 12 installed in the vehicle30 accepts the disablement information DI via the receiver 33.Accordingly, the operation control of the controlled device 31 by thecontrol device 12 is disabled (NO in STEP13 and STEP15 of FIG. 3 ).

When the processing in FIG. 4 returns to STEP22, the processor 132initiates the walking determination processing again (STEP40). Asdescribed above, the processor 132 determines whether the time period TPis defined (STEP30). In the example illustrated in FIG. 6 , since thetime period TP is defined between the time point t1 and the time pointt2 (YES in STEP30), the processor 132 advances the processing to STEP35,and initiates the processing for defining an end point EP of a next timeperiod TP.

That is, the end point EP of a certain time period TP is treated as thestart point SP of the next time period TP. In the example illustrated inFIG. 6 , the end point EP defined at the time point t2 is defined as thestart point SP of the next time period TP, and the above-describedcondition as for the acceleration change is satisfied again at a timepoint t3 after the time point t2. Accordingly, the end point EP of thenext time period TP is defined at the time point t3. Namely, the timepoint t2 is an example of the first time point, and the time point t3 isan example of the second time point.

Except in a case where the end point EP is not determined after theprescribed time period has elapsed (YES in STEP36), the definition of anew time period TP and the walking determination based on the waveformportion of the acceleration signal AS included in the defined timeperiod are repeated (STEP35, STEP37, and STEP38).

When it is determined that the waveform portion of the accelerationsignal AS included in the time period TP between the time point t2 andthe time point t3 does not satisfy the condition as for walking (NO inSTEP38), the processor 132 determines that the authenticated person 20is not walking (STEP33), and terminates the processing. The result isreflected in the processing of STEP23 in FIG. 4 . That is, after thetime point t3, the mobile device 11 wirelessly transmits the enablementinformation EI (STEP24). Accordingly, the operation of the controlleddevice 31 can be enabled by the control device 12 (YES in STEP13 andSTEP14 of FIG. 3 ).

When it is determined that the waveform portion of the accelerationsignal AS included in the time period TP between the time point t2 andthe time point t3 satisfies the condition as for walking (YES inSTEP38), the processor 132 determines that the authenticated person 20is walking (STEP39), and terminates the processing. The result isreflected in the processing of STEP23 in FIG. 4 . That is, after thetime point t3, the mobile device 11 wirelessly transmits the disablementinformation DI (STEP25). Accordingly, the operation control of thecontrolled device 31 by the control device 12 is disabled (NO in STEP13and STEP15 of FIG. 3 ).

When the processing in FIG. 4 returns to STEP22, the walkingdetermination processing is repeated in the same manner even after thetime point t3.

In the present embodiment, the time period TP is defined based on acondition prescribed so as to include a waveform portion in theacceleration signal AS outputted from the acceleration sensor 113 thatmay represent a state that the authenticated person 20 is walking. Inaddition, by referring to the feature quantity for the waveform portion,it is verified whether the authenticated person 20 is walking. As aresult, the accuracy of the walking determination processing isimproved. Accordingly, it is possible to improve the convenience of theauthentication system 10.

In addition to or in place of the walking determination processing(STEP38 in FIG. 5 ) based on the waveform portion of the accelerationsignal AS included in the time period TP described with reference toFIG. 7 , a plurality of feature quantities illustrated in FIG. 8 can bereferred to in the walking determination processing. Specifically, thetime period TP defined as time between the start point SP and the endpoint EP is divided into a first time sub-period and a second timesub-period by a time point CP at which the increasing accelerationmatches the threshold At. Here, examples of the plurality of featurequantities that can be referred to at this are listed below.

T3: a time length from the start point SP to the time point CP

T4: a time length from time CP to the end point EP

T5: a time length from the start point SP to a time point at which theacceleration takes the minimum value Amn

T6: a time length from the time point CP to a time point at which theacceleration takes the maximum value Amx

Amn: the minimum value of the acceleration in the first time sub-period

Amx: the maximum value of acceleration in the second time sub-period

M3: a mean value of the acceleration in the first time sub-period

M4: a mean value of the acceleration in the second time sub-period

G1: an amount of change in the acceleration per unit time from the startpoint SP to the time point at which the acceleration takes the minimumvalue Amn

G2: an amount of change in the acceleration per unit time from the timepoint when the acceleration takes the minimum value Amn to the timepoint CP

G3: an amount of change in the acceleration per unit time from the timepoint CP to the time point at which the acceleration takes the maximumvalue Amx

G4: an amount of change in the acceleration per unit time from the timepoint at which the acceleration takes the maximum value Amx to the endpoint EP

It should be noted that it is not necessary to refer to all of thefeature quantities listed above. At least one of the plurality offeature quantities listed above may be referred to.

According to such a configuration, it is possible to perform moredetailed and precise walking determination processing based on theacceleration signal AS outputted from the acceleration sensor 113.Accordingly, the accuracy of the walking determination processing isfurther enhanced.

As illustrated in FIG. 2 , the trigger signal TS transmitted from thetransmitter 32 of the vehicle 30 is received by the receiver 111 of themobile device 11, and is accepted by the reception interface 131 of theprocessing device 13. In the activation processing (STEP21) describedwith reference to FIG. 4 , in addition to the above-describedauthentication processing, the activation processing of the accelerationsensor 113 illustrated in FIG. 9 is executed.

Specifically, the processor 132 determines whether the receptioninterface 131 receives the trigger signal TS (STEP41). This processingis repeated until the acceptance is confirmed (NO in STEP41).

When it is confirmed that the trigger signal TS is accepted (YES inSTEP41), the processor 132 activates the acceleration sensor 113(STEP42). As a result, the output of the acceleration signal AS from theacceleration sensor 113 is initiated. The time point t0 in FIG. 6corresponds to a time point when the acceleration sensor 113 isactivated.

It should be noted that the trigger signal TS may be directly inputtedfrom the receiver 111 to the acceleration sensor 113 to activate theacceleration sensor 113.

That is, when the mobile device 11 wirelessly receives the triggersignal TS, the walking determination processing for determining whetherthe authenticated person 20 is walking is initiated. In other words, theacceleration sensor 113 and the walking determination processing are ina standby state until the mobile device 11 receives the trigger signalTS. The term “standby state” means a state that power consumption isless than a state that the output of the acceleration signal AS can beexecuted. A state that no power is consumed is also included in the“standby state”. According to such a configuration, since powerconsumption in the mobile device 11 can be suppressed, it is possible toimprove the convenience of the authentication system 10.

The processor 132 having various functions described above can beimplemented by a general-purpose microprocessor operating in cooperationwith a general-purpose memory. Examples of the general-purposemicroprocessor include a CPU, an MPU, and a GPU. Examples of thegeneral-purpose memory include a ROM and a RAM. In this case, a computerprogram for executing the above-described processing can be stored inthe ROM. The ROM is an example of a non-transitory computer-readablemedium having recorded a computer program. The general-purposemicroprocessor designates at least a part of a computer program storedin the ROM, loads the program on the RAM, and executes the processingdescribed above in cooperation with the RAM. The above-describedcomputer program may be pre-installed in the general-purpose memory, ormay be downloaded from an external server device 50 via a wirelesscommunication network 40 illustrated in FIG. 1 and then installed in thegeneral-purpose memory. In this case, the external server device 50 isan example of a non-transitory computer-readable medium having stored acomputer program.

The processor 132 having various functions described above may beimplemented by a dedicated integrated circuit capable of executing theabove-described computer program, such as a microcontroller, an ASIC,and an FPGA. In this case, the above-described computer program ispre-installed in a memory element included in the dedicated integratedcircuit. The memory element is an example of a non-transitorycomputer-readable medium having stored a computer program. The processor132 may also be implemented by a combination of the general-purposemicroprocessor and the dedicated integrated circuit.

The above embodiments are merely illustrative for facilitatingunderstanding of the gist of the presently disclosed subject matter. Theconfiguration according to the above embodiment can be appropriatelymodified or improved without departing from the gist of the presentlydisclosed subject matter.

In the above embodiment, in response to the trigger signal TS, theprocessing device 13 transmits the authentication information AI throughthe transmitter 112 installed in the mobile device 11. However, theprocessor 13 may be configured to transmit an acknowledgement signal tothe control device 12 in response to the trigger signal TS. In thiscase, the control device 12 that receives the acknowledgement signal maybe configured to transmit a request signal for requesting the processingdevice 13 to transmit the authentication information AI. In such aconfiguration, the trigger signal TS can be regarded as a signal forinitiating the authentication processing.

In the above embodiment, the trigger signal TS for initiating theauthentication processing when received by the mobile device 11 is usedin combination for initiating the walking determination processing basedon the acceleration sensor 113. According to such a configuration, it isnot necessary to provide an additional communication circuit, and it ispossible to suppress an increase in the cost of the device and anincrease in the size of the device. However, a wireless signalindependent of the trigger signal TS for initiating the authenticationprocessing may be used for activating the acceleration sensor 113. Forexample, a dedicated signal for activating the acceleration sensor 113may be transmitted from the transmitter 32 installed in the vehicle 30.

Alternatively, a radio signal for initiating appropriate processing thatmay be performed in the processing device 13 of the mobile device 11 maybe used for activating the acceleration sensor 113. Examples of such aradio signal include the request signal described above, a signal formaking a power saving operation of the mobile device 11 effective orineffective, and the like. Alternatively, a signal available in anin-vehicle network for indicating a security state of the vehicle 30 (asignal indicating a locked/unlocked state of the door, a signalindicating an open/closed state of the door, and the like) may bewirelessly transmitted from the transmitter 32 and used for activatingthe acceleration sensor 113.

The activation of the acceleration sensor 113 is not limited to a casewhere various radio signals as described above are received by thereceiver 111 installed in the mobile device 11. For example, theacceleration sensor 113 can be activated when a signal strength of anykind of radio signal received by the receiver 111 exceeds a prescribedthreshold.

As used herein, the expression “activating an acceleration sensor” isnot intended to depict only a case where the acceleration sensor 113 istransitioned from an inoperative state to an operative state. Theexpression may depict a case where a transition is made from a statethat the walking determination processing using the acceleration sensor113 is disabled to a state that the walking determination processing isenabled. For example, a transition from a state that the accelerationsensor 113 is operating at a sampling rate low enough to disable thewalking determination processing to a state that the acceleration sensor113 is operating at a sampling rate high enough to eable the walkingdetermination processing may also be an example of the “activation”.

In the above embodiment, the processing device 13 is installed in themobile device 11. According to such a configuration, it is easy tosuppress a communication delay that may occur when a result of thewalking determination processing is provided to the control device 12through wireless communication.

However, the processing device 13 may be installed in the externalserver device 50 illustrated in FIG. 1 . In this case, the accelerationsignal AS outputted from the acceleration sensor 113 of the mobiledevice 11 is transmitted from the transmitter 112 to the external serverdevice 50 via the wireless communication network 40. The processingdevice 13 installed in the external server device 50 executes thewalking determination processing described above based on the receivedacceleration signal AS. The external server device 50 transmits theenablement information EI or the disablement information DI obtained asa result of the walking determination processing to the receiver 33 ofthe vehicle 30 via the wireless communication network 40. The controldevice 12 determines whether the operation of the controlled device 31is enabled based on the received enablement information EI or thereceived disablement information DI. The result of the walkingdetermination processing may be returned from the external server device50 to the receiver 111 of the mobile device 11 via the wirelesscommunication network 40.

At least a part of the authentication processing can be performed in theexternal server device 50. That is, at least one of the function of theprocessor 132 of the processing device 13 for providing theauthentication information AI, the function of the storage device 14 forstoring the authentication information AI, and the function of theprocessor 121 of the control device 12 for collating the authenticationinformation AI provided from the processor 132 with the authenticationinformation AI stored in the storage device 14 can be shared by theexternal server device 50.

For example, the mobile device 11 having received the trigger signal TSmay request the external server device 50 to provide the authenticationinformation AI via the wireless communication network 40. When receivingthe request, the external server device 50 transmits the authenticationinformation AI to the receiver 33 of the vehicle 30 via the wirelesscommunication network 40. The control device 12 determines whether theauthentication is approved based on the received authenticationinformation AI. The authentication information AI may be returned fromthe external server device 50 to the receiver 111 of the mobile device11 via the wireless communication network 40.

Alternatively, the mobile device 11 having received the trigger signalTS transmits the authentication information AI from the transmitter 112to the external server device 50 via the wireless communication network40. The external server device 50 storing the authentication informationAI in place of the storage device 14 collates the receivedauthentication information AI, and determines whether the authenticationis approved. The external server device 50 transmits the result of theauthentication processing to the receiver 33 of the vehicle 30 via thewireless communication network 40. The control device 12 determineswhether the operation control of the controlled device 31 is enabledbased on the result of the received result of the authenticationprocessing.

The control device 12 may be installed in a mobile entity other than thevehicle 30. Examples of the mobile entity include railways, aircrafts,and ships. The mobile entity may not require a driver.

The controlled device 31 whose operation is controlled by the controldevice 12 in cooperation with the mobile device 11 need not be installedin a mobile entity such as the vehicle 30. The control device 12 may bea device for controlling the operation of a locking device, an airconditioner, a lighting device, an audio-visual equipment, and the likein a house or a facility.

The present application is based on Japanese Patent Application No.2020-051248 filed on Mar. 23, 2020, and Japanese Patent Application No.2021-014115 filed on Feb. 1, 2021, the entire contents of which areincorporated herein by reference.

What is claimed is:
 1. An authentication system, comprising: a mobile device adapted to be carried by a person to be authenticated; an acceleration sensor installed in the mobile device and configured to output an acceleration signal corresponding to acceleration applied to the mobile device; a processor configured to execute determination processing for determining whether the person is walking based on the acceleration signal; and a control device configured to wirelessly transmit a radio signal to the mobile device, wherein the acceleration sensor and the determination processing by the processor are in a standby state until the mobile device receives the radio signal from the control device, so that the determination processing is activated in response to reception of the radio signal by the mobile device; and wherein the control device is configured to control an operation of a controlled device based on a result of the determination processing and a result of authentication processing for authenticating the person as a user of the controlled device.
 2. The authentication system according to claim 1, wherein in a case where a determination that the person is walking is validated by the processor, the control of the controlled device based on the authentication processing is disabled.
 3. The authentication system according to claim 1, wherein the radio signal is used to activate the authentication processing.
 4. The authentication system according to claim 1, wherein the processor is installed in the mobile device.
 5. A mobile device adapted to be carried by a person to be authenticated and to perform wireless communication with a control device configured to execute authentication processing for authenticating the person as a user of a controlled device, the mobile device comprising: a receiver configured to receive a radio signal wirelessly transmitted from the control device; an acceleration sensor configured to output an acceleration signal corresponding to acceleration applied to the mobile device; and a processor configured to execute determination processing for determining whether the person is walking based on the acceleration signal, and to output a result of the determination processing to the control device, wherein the acceleration sensor and the determination processing by the processor are in a standby state until the mobile device receives the radio signal from the control device, so that the determination processing is activated in response to reception of the radio signal by the receiver.
 6. The mobile device according to claim 5, wherein the processor is configured to activate the authentication processing based on the radio signal.
 7. An authentication system, comprising: a mobile device adapted to be carried by a person to be authenticated; an acceleration sensor installed in the mobile device and configured to output an acceleration signal corresponding to acceleration applied to the mobile device; a processor configured to define a time period as time between a first time point at which the acceleration signal satisfies a prescribed condition and a second time point at which the acceleration signal satisfies the prescribed condition again before a prescribed time period is elapsed from the first time point, and to execute determination processing for determining whether the person is walking based on a feature quantity associated with the waveform portion of the acceleration signal within the time period; and a control device configured to control an operation of a controlled device based on a result of the determination processing and a result of authentication processing for authenticating, by way of the mobile device, the person as a user of the controlled device, wherein the prescribed condition includes an acceleration represented by the acceleration signal that changes from a first value more than a first threshold to a second value less than the first threshold, and an amount of change in the acceleration per unit time that exceeds a second threshold; and wherein the feature quantity includes at least one of: a time length between specific points in the waveform portion; a value of the acceleration at a specific point in the waveform portion; a difference between values of the acceleration at the specific points in the waveform portion; a statistic value of the acceleration at the specific point in the waveform portion; a difference between statistic values of the acceleration at the specific points in the waveform portion; and an amount of change in the acceleration per unit time between the specific points in the waveform portion.
 8. The authentication system according to claim 7, wherein in a case where a determination that the person is walking is validated by the processor, the control of the controlled device based on the authentication processing is disabled.
 9. The authentication system according to claim 7, wherein the time period includes a plurality of time sub-periods divided by at least one time point at which the acceleration signal satisfies a prescribed condition; and wherein the processor is configured to refer to, as the feature quantity, a feature quantity associated with a waveform sub-portion of the acceleration signal included in at least one of the time sub-periods.
 10. The authentication system according to claim 7, wherein the processor is installed in the mobile device.
 11. A mobile device adapted to be carried by a person to be authenticated, comprising: an acceleration sensor configured to output an acceleration signal corresponding to acceleration applied to the mobile device; and a processor configured to: define a time period as time between a first time point at which the acceleration signal satisfies a prescribed condition and a second time point at which the acceleration signal satisfies the prescribed condition again before a prescribed time period is elapsed from the first time point; to execute determination processing for determining whether the person is walking based on a feature quantity associated with the waveform portion of the acceleration signal within the time period; and to output a result of the determination processing to a control device configured to execute authentication processing for authenticating the person as a user of a controlled device, wherein the prescribed condition includes an acceleration represented by the acceleration signal that changes from a first value more than a first threshold to a second value less than the first threshold, and an amount of change in the acceleration per unit time that exceeds a second threshold; and wherein the feature quantity includes at least one of: a time length between specific points in the waveform portion; a value of the acceleration at a specific point in the waveform portion; a difference between values of the acceleration at the specific points in the waveform portion; a statistic value of the acceleration at the specific point in the waveform portion; a difference between statistic values of the acceleration at the specific points in the waveform portion; and an amount of change in the acceleration per unit time between the specific points in the waveform portion.
 12. A processing device, comprising: a reception interface configured to accept an acceleration signal corresponding to acceleration applied to a mobile device adapted to be carried by a person to be authenticated from an acceleration sensor installed in the mobile device; and a processor configured to: define a time period as time between a first time point at which the acceleration signal satisfies a prescribed condition and a second time point at which the acceleration signal satisfies the prescribed condition again before a prescribed time period is elapsed from the first time point; to execute determination processing for determining whether the person is walking based on a feature quantity associated with the waveform portion of the acceleration signal within the time period; and to output a result of the determination processing to a control device configured to execute authentication processing for authenticating, by way of the mobile device, the person as a user of a controlled device, wherein the prescribed condition includes an acceleration represented by the acceleration signal that changes from a first value more than a first threshold to a second value less than the first threshold, and an amount of change in the acceleration per unit time that exceeds a second threshold; and wherein the feature quantity includes at least one of: a time length between specific points in the waveform portion; a value of the acceleration at a specific point in the waveform portion; a difference between values of the acceleration at the specific points in the waveform portion; a statistic value of the acceleration at the specific point in the waveform portion; a difference between statistic values of the acceleration at the specific points in the waveform portion; and an amount of change in the acceleration per unit time between the specific points in the waveform portion.
 13. A non-transitory computer-readable medium having stored a computer program adapted to be executed by a processor of a processing device and configured to, when executed, cause the processing device to: accept an acceleration signal corresponding to acceleration applied to a mobile device adapted to be carried by a person to be authenticated from an acceleration sensor installed in the mobile device; define a time period as time between a first time point at which the acceleration signal satisfies a prescribed condition and a second time point at which the acceleration signal satisfies the prescribed condition again before a prescribed time period is elapsed from the first time point; execute determination processing for determining whether the person is walking based on a feature quantity associated with the waveform portion of the acceleration signal within the time period; and output a result of the determination processing to a control device configured to execute authentication processing for authenticating, by way of the mobile device, the person as a user of a controlled device, wherein the prescribed condition includes an acceleration represented by the acceleration signal that changes from a first value more than a first threshold to a second value less than the first threshold, and an amount of change in the acceleration per unit time that exceeds a second threshold; and wherein the feature quantity includes at least one of: a time length between specific points in the waveform portion; a value of the acceleration at a specific point in the waveform portion; a difference between values of the acceleration at the specific points in the waveform portion; a statistic value of the acceleration at the specific point in the waveform portion; a difference between statistic values of the acceleration at the specific points in the waveform portion; and an amount of change in the acceleration per unit time between the specific points in the waveform portion. 